Looks like the reason is pretty simple: the Steam version is 64-bit and the Itch version is 32-bit-only. Please fix this.
OH I see! The 64 bit version is uploaded. I switched Linux64 to be first, perhaps that'll help?
Yes, that fixed it. Thanks!
Weird - I could swear that there wasn't a 64-bit option when I first installed it, but I definitely could've just not noticed it. It's probably good to make the 64-version the default anyway because so few people use 32-bit Linux anymore.